Sorry she is having these problems OP. In high school, anything that makes you different from other kids is a "problem"--I was large and tall, which was a "problem" too. Best if you can get her to value herself now, as she is, and see the potential advantages to being petite.

OP, I have an adopted son who is petite and size is an adoption issue for him as well. He has FASD and one of the side effects of his birth mother's drinking is low weight and height. He also has cognitive issues as well. The whole thing is very difficult for him but the outward sign (small size) makes it so much worse because it is an ever present sign and reminder. I have no ideas for you. For my son, I work hard to help him make choices and decisions that will lead to success as an adult and hope that at some point he can move on from the anger. We tried counseling but it was unhelpful.

I am adopted and have always had very pronounced muscles. I was an athlete in high school and college and during the season I always felt like I was too bulky, almost mannish. Fast forward 10 years and I am now an Olympic weightlifter, extremely strong for my height and weight (carry 120lb lean mass with 15% body fat), and my body image has greatly improved. While I used to hate my muscular build, now it is something I'm proud of. I am at terms with being adopted, but am curious what my parents genetics were like. Not knowing that, I didn't have to think that "this is all I'll ever be because my mom looks like that." I just put in a ton of hard work and realized that certain things came easier to me than others and decided to maximize my potential. There are still people who say I look like a man, I need implants, I should cut back on the lifting or eating. To each their own. At some point your daughter will embrace her unique build and grow to accept and love it. Your job is just to encourage her.

I think your take away from this, OP, is that all women (ALL WOMEN) have body issues. While you may see a connection between the adoption and her concerns about being petite, you see that we all share the same experience----fat, slim, tall, short. We ALL confront this, and at many points in our lives as well. This is the first of many instances where she'll look to her body with discomfort.